Device for Throughfeed of Greywater to a Water User, Greywater System Provided Therewith and Method for Applying Same

ABSTRACT

The invention relates to a device for throughfeed of greywater to a water user, including a housing for receiving therein greywater supplied via a greywater feed, a first flush pipe extending downward from the housing and connected directly to a sewer outlet, and a second flush pipe extending downward from the housing and connected to a water user. The invention further includes a greywater system provided with such a device and method for applying same.

The present invention relates to a device for throughfeed of greywater to a water user, more particularly for immediate use thereof by the water user, in addition to a greywater system provided therewith and method for applying same.

One method of making efficient use of energy and environment is to reuse lightly contaminated water. Instead of mains water, which is treated with considerable effort and at a great cost in wastewater purification plants, less clean non-potable water can be used for some applications, such as for instance flushing the toilet. It is thus possible to envisage the use of collected rainwater and the reuse of lightly contaminated bath and shower water, as well as water that has been used by dishwashers and washing machines. Such lightly contaminated water is also referred to as greywater. The saving of water resulting from the reuse of water furthermore results in a proportional reduction in the stress on the sewage system.

There is a continuing need for greywater systems which are easy to assemble.

An object of the present invention is to at least partially obviate at least one or more drawbacks of the prior art.

The stated objective is achieved with the device for throughfeed of greywater to a water user according to the present invention, comprising:

-   -   a housing for receiving therein greywater supplied via a         greywater feed;     -   a first flush pipe extending downward from the housing and         connected directly to a sewer outlet; and     -   a second flush pipe extending downward from the housing and         connected to a water user.

Such a device has the advantage that a cistern of the water user becomes unnecessary.

According to a preferred embodiment, these parts together form a modular unit which can be arranged on a water storage unit. Because the modular unit comprises substantially all moving parts of the greywater system, the greywater system comprises, in addition to this modular unit, only several basic elements such as a frame, a water storage unit, a front wall and a control system. The modular unit hereby reduces a greywater system to a system which can be assembled relatively easily from basic elements.

According to a further preferred embodiment, at least one of the flush pipes is controlled by a solenoid, wherein the core of the solenoid is connected to a spring.

According to yet another preferred embodiment, the solenoid is further provided with a permanent magnet, preferably a shock-resistant supermagnet manufactured from NdFeB. A permanent magnet has the advantage that it can be controlled by means of pulses and that no energy is used during rest—both in an attracted and repelled rest state. A supermagnet in N45 (1.37 Tesla) has been found suitable.

According to yet another preferred embodiment, the permanent magnet is arranged in the core of the solenoid. Although it is possible to envisage the permanent magnet being arranged in the coil of the solenoid, arranging the permanent magnet in the core has the advantage that the play of forces is more advantageous than when the magnet is arranged in the coil. Placing a magnet in the core runs counter to the prejudice that magnets lose their magnetism under shock load.

The invention also relates to a system for reusing greywater, comprising:

-   -   a collecting reservoir for collecting therein greywater supplied         via a water feed;     -   a storage tank for storing water;     -   siphoning means for siphoning water from the collecting         reservoir to the storage tank; and     -   a device as described in the foregoing for discharging stored         water to a water user therewith.

In a preferred embodiment the system comprises a control system (ECU) for thereby controlling inter alfa actuators present in the system.

According to a further preferred embodiment, the siphoning means comprise:

-   -   a siphon connection for siphoning water collected in the         collecting reservoir from the collecting reservoir to the         storage tank;     -   pressure regulating means for thereby regulating the pressure in         the storage tank, with which possible overpressure in the         storage tank can be relieved so that siphoning of water from the         collecting reservoir to the storage tank can take place; and     -   wherein the siphon connection is arranged substantially in a         middle zone B of the collecting reservoir which is arranged         substantially upright.

According to yet another preferred embodiment, the collecting reservoir and the storage tank form part of an integrally manufactured water storage unit.

According to yet another preferred embodiment, the greywater system further comprises:

-   -   a water user, particularly a toilet, not having its own water         reservoir; and     -   wherein the device specified in the foregoing is adapted to         thereby discharge stored water to the water user for immediate         use thereof without interposing of a water reservoir of the         water user.

According to yet another preferred embodiment, the greywater system further comprises:

-   -   determining means for determining the quantity of water stored         in the system; and     -   influencing means for thereby influencing the quantity of water         flowing from the storage tank to a water user.

In contrast to a standard cistern of a toilet, the outflow characteristic of which is known and is moreover substantially constant—since it will generally be (almost) completely full when flushed—the use of a relatively large storage tank from which water is discharged directly to a water user—so not via a cistern—has the drawback that the outflow characteristic can vary greatly according to the quantity of water stored in the storage tank, which variation can lie typically in the range of 10-100 litres. About 6 litres is used as a minimum volume, while a storage tank can for instance store up to as much as 100 litres of greywater. The volume flow, or the flow rate, of the water flowing from the storage tank to a water user depends on the water level in the storage tank, the outflow opening and the time.

The determining means can particularly be adapted to determine the height of the water level in the water storage unit, for instance by means of a float, such as the float present in the greywater device according to the invention which activates the emergency replenishment. In the case of a fixed form of the water storage unit the volume can however also be determined in other manner, after which it is known which outflow characteristic will occur during the outflow to the water user.

Depending on the outflow characteristic expected on the basis of the quantity of water present in the storage tank, the outflow opening or the time is then adapted such that a desired quantity of water is flushed from the storage tank to the water user.

According to yet another preferred embodiment, the collecting reservoir of the greywater system comprises a volume of at least 10 litres so that sufficient greywater for at least two successive flushes can be stored therein. The collecting reservoir is hereby distinguished from a conventional cistern of a toilet, which can only store sufficient water for a single flush. A flush amount for flushing the toilet generally lies in the range of 4-6 litres of water. The collecting reservoir, which comprises at least 10 litres of volume, is therefore able to store sufficient greywater for at least two successive flushes. The toilet can thus be flushed at least twice with a usual flushing volume of about 5 litres without interim feed of (grey)water to the collecting reservoir.

Applying large volumes for the collecting reservoir does however have the drawback that the outflow characteristic can vary greatly with the quantity of water stored in the storage tank, for which the present invention compensates.

According to yet another preferred embodiment, the influencing means comprise a throttle or pinch valve controlled by a control system of the greywater system.

According to yet another preferred embodiment, the influencing means, controlled by a control system of the greywater system, adjust the period of time for which the flush opening is open.

According to yet another preferred embodiment, the greywater system further comprises:

-   -   a conduit system between the storage tank and a water user         located at some distance; and     -   a pump for thereby pumping water out of the storage tank to the         water user. The advantage hereof is that a cistern is also         unnecessary for further water users, such as a toilet which is         located at some distance and which can even be situated on a         higher floor.

A water conduit with monitoring of unauthorized addition of branches is preferably applied. Such a water conduit is the subject of Netherlands patent NL 1031270 of applicant.

According to yet another preferred embodiment, the basic volume of water present in the storage tank is increased for each additional water user connected to the system.

The storage tank is always kept filled with a determined quantity of water for at least one flush of a toilet, for instance 6 litres. If there is no supply of greywater, the storage tank is replenished with mains water via the emergency replenishment until the desired basic volume of 6 litres of water is reached.

Since all water users, such as toilets, can theoretically consume water simultaneously when these toilets are flushed simultaneously, the minimum basic volume of water present in the storage tank is increased when a plurality of toilets are connected. The likelihood of simultaneous flushing will of course decrease as the number of toilets increases, whereby a smaller extra quantity of basic volume need be reserved each time for each additional toilet.

According to yet another preferred embodiment, at least 10 litres of water is adhered to as basic volume for two water users.

The invention further relates to a method for throughfeed of water to a water user as described in the foregoing description and/or shown in the accompanying figures.

The invention further relates to a method for reusing greywater as described in the foregoing description and/or shown in the accompanying figures.

In the following description preferred embodiments of the present invention are further elucidated with reference to the drawing, in which:

FIG. 1 is a perspective view of a greywater system according to the present invention;

FIG. 2 is a cross-sectional front view of the greywater device shown in FIG. 1;

FIGS. 3-7 show different successive states of the system during use;

FIG. 8 is a perspective detail view of a modular unit according to the present invention;

FIG. 9 is an enlarged perspective detail view of the modular unit shown in FIG. 8;

FIG. 10 is a cross-sectional side view of the greywater device shown in FIG. 1;

FIG. 11 is an enlarged detail view of the top side of the device shown in FIG. 10;

FIG. 12 is a schematic view of the operation of the solenoids with rod mechanism and compression spring shown in FIG. 11;

FIGS. 13A-13D show four successive stages during the process of lifting a flush pipe using the construction shown in FIG. 12;

FIGS. 14A-14C show force versus lift height characteristics according to the present invention;

FIG. 15 is an enlarged schematic view of the device shown in FIG. 2;

FIG. 16 is a top view of the device shown in FIG. 1; and

FIG. 17 is an enlarged detail view of the top view shown in FIG. 16.

FIG. 1 is a perspective view of a greywater system 1 comprising a water storage unit 5 consisting of a collecting reservoir 2 and a storage tank 4. In addition to water storage tank 5 greywater system 1 comprises a support frame 28, a control unit (not shown) and a modular unit in which are accommodated, among others, the following parts to be further described hereinbelow: a housing 38 with a cover 40 in which a number of openings are present, including an opening 42 for the feed of greywater and an opening 43 to which is connected an emergency replenishment 54 for feed of mains water. In addition, two solenoids 44, 46 with which flush pipes 48, 50 can be displaced are arranged on cover 40 of housing 38.

Running from housing 38 of the modular unit is a bypass conduit 10 through which light contaminants—in a manner as will be elucidated hereinbelow—will be discharged to the sewer outlet.

Situated on the underside of water storage unit 5 is a conduit 30 from a drainage opening 24 to a connecting point 31 for the feed of (grey)water to a water user (not shown) such as a toilet.

Water storage unit 5 also comprises a drainage opening 26 to which a conduit 32 is connected for discharging water from water storage unit 5 to sewer outlet 34.

The greywater system shown in FIG. 1 is shown in cross-sectional views in FIGS. 2, 10 and 16, respectively from the front (FIG. 2) from the right-hand side (FIG. 10) and from the top (FIG. 16).

In the cut-away cross-sectional view of FIG. 2 solenoids 44, 46 for respectively controlling the flush pipe 48 to a water user and a flush pipe 50 to sewer outlet 34 are placed one directly behind the other, this also being the case for flush pipes 48, 50 themselves.

When greywater is supplied via opening 43 (not visible in FIG. 2), it is collected in collecting reservoir 2, which forms part of water storage unit 5. On the underside this storage unit 5 is closed by flush pipe 48, which closes a drainage opening 24 to a water user (not shown), and by flush pipe 50, which closes a drainage opening 26 to sewer outlet 34. A float 62 is arranged slidably along flush pipes 48, 50 and—with varying water level in collecting reservoir 2—operates, by means of a float rod 64, a closing valve 60 which regulates the supply of mains water via mains water feed 58 in emergency replenishment 54. This emergency replenishment 54 has a housing 56 and a cover 57, and in the bottom of housing 56 a conduit 66 through which mains water can be guided to collecting reservoir 2. It is noted that there is some height difference between the underside of conduit 66 and the top side of collecting reservoir 2, whereby a so-called air bridge is created here which—if the sewer is blocked—prevents greywater coming into contact with mains water.

In an alternative embodiment (not shown) the emergency replenishment 54 is activated electronically on the basis of a sensor arranged in collecting reservoir 2 for measuring the volume of greywater present therein, such as for instance using a height detector which determines on the basis of pressure the height of the water level.

An air bridge is also arranged in housing 56 of emergency replenishment 54, which will be further elucidated below with reference to FIG. 15.

Further situated in cover 40 of housing 38 of the modular unit is an opening 41 through which the pressure regulating means 18, which are formed by a tube 22 and an air valve 20, can influence the air pressure level in storage tank 4 as required by optionally opening air valve 20.

Housing 38 of the modular unit is arranged watertightly on the underside onto collecting reservoir 2 by means of a seal 52.

When use is made of shower and bath, the mains water used for this purpose will become contaminated. Instead of allowing this water to disappear directly into the sewer, it is collected via a feed 14 in collecting reservoir 2, which will thereby be filled with greywater. Drainage openings 30, 32 and pressure regulating means 18 are closed, whereby the water level in collecting reservoir 2 will rise when greywater is delivered via feed 14.

Greywater collected directly from bath and shower contains contaminants such as sand, soap suds, grease, flakes of skin and hair, thereby making a form of separation or filtering desirable. A separating principle is applied by the shown greywater system based on a difference in density or specific weight between the water and the contaminants present in the water.

Arranged at the top of collecting reservoir 2 is an overflow 6 where greywater flows away to the sewer via a bypass conduit 10 and a sewer outlet 34. Contaminants with a density lower than that of water (ρ_(contaminant)<ρ_(water)), such as for instance soap suds, will float and therefore be drained together with the greywater via overflow 6 and bypass conduit 10 in the direction of the sewer. In order to prevent contaminants continuing to float on the top, a skimmer 8 is arranged for skimming off these contaminants in the direction of bypass conduit 10.

The relatively heavy contaminants, such as for instance sand particles, with a density which is greater than that of water (ρ_(contaminant)>ρ_(water)), will be collected due to settling at the bottom of collecting reservoir 2. Because light contaminants will float and heavy contaminants will sink, the cleanest water will be situated substantially in a middle zone B, i.e. between the top and bottom of collecting reservoir 2.

Three zones are thus formed, respectively a lower zone A where relatively heavy particles have settled, an upper zone C in which a cloud of relatively light, floating contaminants will form, and therebetween a middle zone B in which relatively clean water is located.

Since heavy particles such as sand settle relatively quickly, at least generally sink much more quickly than light particles rise, lower zone A will be smaller than upper zone C as seen in height direction. Furthermore, supplied greywater generally contains more ‘light’ contaminants than ‘heavy’ contaminants. Middle zone B is situated between zones A and C and, due to the small height of bottom zone A in height direction of collecting reservoir 2, generally extends further downward than upward.

In the shown embodiment collecting reservoir 2 and storage tank 4 form part of an integrally injection-moulded water storage unit 5, but can of course also comprise physically separated volume tanks.

The operation of the separating principle applied in greywater system 1, which is the subject of the Netherlands patent NL 1030110 of applicant, will be described with reference to FIGS. 3-7.

FIG. 2 shows a water storage unit 5 comprising a storage reservoir 2 and a storage tank 4 consisting of a left and right-hand half. In the shown design the collecting reservoir 2 is an elongate reservoir which is oriented substantially upright and connected on the underside to storage tank 4, which is arranged on either side of collecting reservoir 2, likewise in substantially upright orientation. As further elucidated hereinbelow, the connection between collecting reservoir 2 and storage tank 4 functions as siphon connection 12 between reservoir 2 and storage tank 4.

The system shown in FIG. 3 is situated in a rest position, wherein about 6 litres of water are received in water storage unit 5 forming collecting reservoir 2 and storage tank 4. In the shown embodiment the water level lies here roughly at a height at which siphon connection 12 is under water.

When greywater is supplied via the schematically shown water feed 14, collecting reservoir 2 will be filled with this supplied greywater and the water level in storage tank 4 will only rise slightly because pressure regulating means 18 are still in a closed position (FIG. 4).

The light contaminants with a density lower than that of water will float and flow away via overflow 6 at the top of collecting reservoir 2, assisted by a skimmer (not shown) if desired. A cloud with light contaminants will form in zone C at the top of collecting reservoir 2. Conversely, heavy particles will sink, whereby a contaminated zone (zone A) is also formed at the bottom of collecting reservoir 2. Relatively clean greywater is located in the middle zone B between lower zone A and upper zone C. Siphon connection 12 is also situated in this clean middle zone B (FIG. 4).

With continuous inflow of greywater via greywater feed 14 the collecting reservoir 2 remains filled, whereby light contaminants are discharged to the sewer close to overflow 6. With preferably pulse-wise opening of pressure regulating means 18, which in the shown preferred embodiment comprise an air valve 20, the overpressure formed in storage tank 4 can escape and the water level in storage tank 4 will rise because water is siphoned from the relatively clean zone B of collecting reservoir 2 via siphon connection 12 to storage tank 4. Opening the one or more air valves 20 in pulsating manner ensures that collecting reservoir 2 remains fully filled during feed of greywater 14, whereby the contaminated zone C with light contaminants will remain located at the top of collecting reservoir 2.

FIG. 6 shows a rest position of the system, wherein water is neither being supplied via water feed 14 nor being discharged to a water user 36 such as a toilet. Due to a large quantity of greywater supplied via water feed 14 the water level in storage tank 4 has however risen considerably relative to the situation shown in FIG. 4, to a level sufficient for flushing a toilet a number of times.

Because the system is at rest, the cloud with contaminants with a density lower than that of water has risen to some extent, whereby the contaminated zone C has become smaller, as seen in height direction, than in the situation shown in FIG. 5. In this rest position the relatively clean middle zone B therefore extends somewhat further toward the top of collecting reservoir 2.

FIG. 7 shows a rest position wherein a flush to a water user 36 has taken place and—because pressure regulating means 18 are opened during the flushing—some levelling has taken place, and the water level in both storage tank 4 and collecting reservoir 2 has fallen slightly. The water level of FIG. 6 is designated with a broken line.

It is noted that the contaminated zone C with substantially light contaminants has also fallen slightly together with the water level in collecting reservoir 2, but that siphon connection 12 between collecting reservoir 2 and collecting reservoir 4 is still situated in the relatively clean middle zone B (FIG. 6).

FIG. 8 shows a perspective view of the modular unit, comprising a housing 38 with a cover 40 and a seal 52 on the underside of housing 38. Situated in cover 40 are openings, such as the opening for greywater feed 42, an opening 43 (not visible) to which the emergency replenishment 54 for the supply of mains water is connected, two openings through which are arranged first solenoid 44 for operating flush pipe 48 to a water user (not shown) and a second solenoid 46 for operating a flush pipe 50 to sewer outlet 34. In addition, an opening 41 (not shown) to which pressure regulating means 18 are connected is arranged in cover 44. The pressure in storage tank 4 can be influenced by means of these pressure regulating means 18, in particular by optionally opening air valve 20. Because storage tank 4 consists of two halves which can become separated from each other by water in the bottom of water storage unit 5, a tube 22 is arranged on the top side of storage tank 4 which provides a gas connection between the two halves of storage tank 4, whereby the air pressure in the two halves of storage tank 4 remains the same.

Emergency replenishment 54 comprises a mains water feed 58 and, on the side wall of housing 56, an opening 68 which functions as air bridge and which will be further elucidated with reference to FIG. 15.

Further shown in FIG. 8 is the bypass conduit 10 through which light contaminants can be discharged to sewer outlet 34.

FIG. 8 further shows how a float 62 operates emergency replenishment 54 by means of a float rod 64 via passage opening 65 in cover 40. This is shown more clearly in the enlarged detail view of FIG. 9.

The cross-sectional view shown in FIG. 10 shows the greywater system 1 shown in FIG. 1 from the right-hand side, wherein it can be clearly seen that solenoids 44, 46 and flush pipes 48, 50 in the front view of the greywater system of FIG. 1 shown in FIG. 2 are situated one behind the other. Situated at the top of collecting reservoir 2 is an overflow 6 over which light contaminants can be discharged via bypass conduit 10 to sewer 34.

Since heavy contaminants sink and are preferably carried away via drainage opening 26 and conduit 32 to sewer outlet 34—instead of being carried away via drainage opening 24 and conduit 30 to a water user—the drainage opening 26 to the sewer is situated in the embodiment shown in FIG. 10 at a lower level than the drainage opening 24 to the water user. Because heavy particles sink, they will accumulate close to the lowest point of collecting reservoir 2 and so collect close to the lower-lying drainage opening 26, from where they are carried away with a periodic flushing to the sewer.

The top side of flush pipes 48, 50 is higher than the top side of collecting reservoir 2.

In a possible further embodiment (not shown) flush pipes 48, 50 have the same length, although around flush pipe 48 which closes the drainage opening 24 to a water user a strainer body is arranged on the underside which functions as a screen for the settled contaminants, which thus remain in collecting reservoir 2 when drainage opening 24 is opened and can be discharged via drainage opening 26 to sewer 34 during a subsequent flush.

It is noted that closing of drainage opening 24, 26 at different heights requires flush pipes 48, 50 of different lengths.

FIG. 11 shows an enlarged view of the upper part of FIG. 10, wherein solenoids 44, 46 are situated in a housing 82 arranged on housing 40 by means of a rotating part 86. Since both solenoids operate in similar manner, they are discussed in more detail with reference to the following FIG. 12.

Each solenoid 44, 46 is arranged in a housing 82, wherein this housing 82 comprises an external screw thread 84 over a part of its outer wall. This external screw thread 84 engages on an internal screw thread of a rotating part 86, whereby housing 82 with solenoid 70 can be adjusted in the height relative to cover 40 of housing 38. The solenoid comprises a coil 70 and a metal core 72, which in a preferred embodiment of the present invention is divided into a conical part 74 and cylindrical part 76, between which is situated a connecting part 78 in the form of a shaft around which a permanent magnet, preferably a supermagnet, is arranged. This magnet is preferably a shock-resistant magnet manufactured from NdFeB (in N45 1.37 Tesla). Although there is a prejudice that magnets are unsuitable for applications where shocks are applied to the magnet because this would cause them to lose their magnetism, applicant has applied said magnets manufactured from NdFeB in the core of the solenoid and has found, surprisingly, that the play of forces is more advantageous than in an embodiment where a permanent magnet is arranged in coil 70. In the case of a magnet in coil 70, the play of forces will after all only become manifest in the final millimetres of the path travelled by the core in coil 70.

Owing to its magnetic force the permanent magnet 80 will hold core 72 drawn into coil 70 of solenoid 44, 46 even when no energy is being provided to the electromagnet. Only when the current is carried in reverse direction through the electromagnet (solenoid 44, 46) will the resultant magnetic force of electromagnet 44, 46 and permanent magnet 80 together be able to equal zero, whereby flush pipe 48, 50 will repel and the discharge of water from storage unit 5 through drainage opening 24, 26 will be stopped. When the number of Ampere Windings (AW) is increased, the downward directed magnetic force generated by electromagnet 44, 46 will be greater than the upward directed magnetic force of permanent magnet 80. This results in a resultant magnetic force in downward direction which brings about ejection of the core.

Since a solenoid 44, 46 develops a relatively low force in the situation shown in FIG. 12, wherein only a small part of metal core 72 is located inside coil 70, which force increases significantly the further core 72 is located in coil 70, a standard solenoid 44, 46 will have to be significantly overdimensioned when it is applied for the purpose of lifting a flush pipe 48, 50 sealing a drainage opening 24, 26. This is because a relatively high threshold value has to be overcome before the flush pipe releases, indicated in FIG. 14 with the first level located at around 0.7 kg of force and a lift height of between 0 and 2 millimetres of the valve formed by the underside of flush pipe 48, 50.

It is noted that the precise lift heights and associated forces depend on the dimensions of the system, including the dimensions of the outflow opening and the water level, and are only mentioned as such with reference to the accompanying Figure in order to provide insight into the physical events therein, but may not be interpreted as being limitative.

Arranged according to the present invention on metal core 72 is a rod 88 which comprises on its outer end a stop constructed from a stop plate 94 and a nut 96. A compression spring 90 is situated between stop plate 94 and housing 82.

This construction of core 72, rod 88, compression spring 90 and stop 94 makes it possible using relatively small solenoids to generate the force required to lift a flush pipe 48, 50, as is shown in FIGS. 13A-13D.

In FIG. 13A core 72 is situated for the greater part outside coil 70 and compression spring 90 is substantially fully extended.

FIG. 13B shows how, by energizing coil 70 of the solenoid, core 72 is pulled partially into this coil 70, herein compressing the compression spring 90. Because core 72 is displaced increasingly further into coil 70, the force generated by this solenoid increases, as can also be seen in the characteristic of FIG. 14. With increased lifting force and compressed spring 90 the core 72 displaces further into coil 70 and herein lifts flush pipe 48, 50 (FIG. 13C), after which spring 90 will extend and flush pipe 58 will be lifted further.

A greywater discharge valve (flush pipe 48, 50) driven by an electromagnet (solenoid 44, 46) with spiral spring 90 and permanent magnet 80 will now be elucidated with reference to FIGS. 14A-14C.

An electromagnet with movable core of soft iron, such as solenoid 44, 46, has the property in the extended state (on the left in FIG. 14A) of being able to exert a small pulling force, while the greatest pulling force occurs in retracted state (on the right in FIG. 14A)—see the continuous curve a in FIG. 14A.

It is however precisely in the extended state that a greywater discharge valve, such as flush pipe 48, 50, requires the greatest pulling force, while less pulling force is required in the retracted state—see FIG. 14B, curve b. A conventional electromagnet is therefore unsuitable for operating discharge valve 48, 50 of a greywater system.

In the art the electromagnet is therefore briefly overloaded to several times the nominal energy, the force in the extended state will therefore be this many times greater—see FIG. 14A, broken curve c.

When the electromagnet is connected to a large capacitor the voltage on the electromagnet, and thereby the energy of the electromagnet, will briefly be high but then decrease rapidly due to the discharge of the capacitor, and the electromagnet will then not be overloaded here.

As can be seen, the force exerted by the electromagnet using a determined capacitor will still not be sufficient.

In order to be able to achieve a smaller force in the extended state, according to the invention a pull or push spring 90 is connected in series to discharge valve 48, 50. In non-tensioned situation spring 90 exerts zero pulling force, while the pulling force increases linearly during extending. The overall movement of electromagnet core 72 is then however greater—see FIG. 14B.

In this FIG. 14B the spiral spring 90 is represented by curve c and discharge valve 48, 50 is represented per se by curve d. Curve e shows the resultant of spiral spring 90 and discharge valve 48, 50 together.

According to the invention a system is provided which consumes no energy when at rest, as elucidated in the following.

By incorporating into electromagnet 44, 46 a permanent magnet 80 which holds core 72 in the retracted position the electromagnet 44, 46 is able to hold discharge valve 48, 50 open in the attracted state.

In the case discharge valve 48, 50 must be closed, electromagnet 44, 46 is connected in reverse direction. This also reverses the force field and, when electromagnet 44, 46 is energized with the correct energy and for the correct period of time, the force field of electromagnet 44, 46 will compensate the field of permanent magnet 80. Owing to this compensation of force fields the core will repel due to gravitational force (or push spring 90).

The force exerted by permanent magnet 80 (FIG. 14C, curve f) will support the force of electromagnet 44, 46 (FIG. 14C, curve g), as shown by the resultant curve h.

The construction of an application of a permanent magnet 80 in core 72 is based on unconventional thinking and varies from the general trend—when a permanent magnet 80 is combined with an electromagnet 44, 46—of arranging this permanent magnet 80 in the anchor, outside the core. An attempt is thus made to prevent a permanent magnet 80 losing its magnetism under shock load.

The construction according to the invention recognizes the fact that modern supermagnets, made for instance of NdFeB(N45), are so shock-resistant that they can also be applied in the core. In addition, this is a structurally simpler solution, which is moreover less expensive.

The method of operation of an electromagnet with permanent magnet in the core does however differ in one respect from the method wherein the permanent magnet is arranged in the anchor outside the core: when the field of the electromagnet is reversed, the core will be ejected from the electromagnet with force because equal poles repel each other.

The amount of energy and the period of time are not critical as they are in the method in which the permanent magnet is arranged in the anchor outside the core.

As can be seen in FIG. 14C, electromagnet 44, 46 with spring 90 and permanent magnet 80 will be able to operate the discharge valve, the force of the electromagnet with supermagnet and spring always being greater than the force required by the discharge valve (curve b).

FIG. 14C shows the lift height of different components of FIG. 12 and the force required for the valve, or flush pipe 48, 50, then the valve when a spring is applied, then the spring only, then a solenoid only, then a supermagnet only and then a combination of solenoid and supermagnet.

The characteristic of the valve only shows that between 0 and 1.5 millimetres of lift height a threshold force of about 0.7 kg must be overcome before an upward trend is continued to a lift height of 5 millimetres and a force of 1.4 kg. The upward trend between 1.5 millimetres and 5 millimetres lift height occurs due to suction caused by water running out of water storage unit 5.

The curve of solenoid with supermagnet is simply the sum of the forces of the solenoid and supermagnet individually, these curves also being shown in FIG. 14.

FIG. 12 further shows an optional stop element 92 which can function as stop during (partial) compression of the spring and can thereby be employed to influence the lift characteristic of flush pipe 48, 50. Stop element 92 prevents the maximum tensioning force of the compression spring being exceeded.

The shown embodiment further shows a sleeve 98 with a plug 100 which encloses rod 88, compression spring 90 and stop 94 in order to enable possible lubrication.

In order to also allow flushing of a toilet in the case of a possible power failure—in which case the solenoids will of course not work—in a preferred embodiment at least a mechanical control is provided with which the flush pipe 48 to the water user can be operated. This mechanical control can for instance comprise a cable or rod (not shown).

FIG. 15 shows an enlarged view of the upper part of FIG. 2, wherein an opening 68, which is situated at a lower level than the feed for mains water via mains water feed 58, is arranged in the side wall of housing 56 of emergency replenishment 54. If in exceptional cases, such as blockage of the sewer or a flood, greywater rises via the sewer through collecting reservoir 2 and were to fill the air bridge between the top side of collecting reservoir 2 and conduit 66, this possibly supplied greywater will then run out of greywater system 1 via opening 68 and so will not be able to come into contact with mains water 58. Due to the opening 68 to the space outside greywater system 1 an air bridge in emergency replenishment 54 remains guaranteed at all times.

FIG. 16 shows a top view of greywater system 1 in which can clearly be seen how the modular unit can be placed as a whole on water storage unit 5. The top view shows pressure regulating means 18 which lead from opening 41 to storage tank 4 and comprise an air valve 20. In addition, these pressure regulating means 18 comprise a tube 22 between the two halves of storage tank 4. Several openings are arranged in cover 40, these being shown in more detail in FIG. 17. These openings comprise an opening for mains water feed 43, to which the emergency replenishment 54 is connected. This emergency replenishment 54 is operated by means of float rod 64, which is movable through cover 40 through passage opening 65. In addition, mounted solenoids 44, 46 are shown which are provided all around with openings 102 for the feed and discharge of air. The cover further comprises an opening 42 for greywater supply and an opening 41 to which pressure regulating means 18 are connected.

Although they show preferred embodiments of the invention, the above described embodiments are intended only to illustrate the present invention and not to limit the specification of the invention in any way. The scope of the invention is therefore defined solely by the following claims. 

1. A device for throughfeed of greywater to a water user, comprising: a housing for receiving therein greywater supplied via a greywater feed; a first flush pipe extending downward from the housing and connected directly to a sewer outlet; and a second flush pipe extending downward from the housing and connected to a water user.
 2. The device as claimed in claim 1, together forming a modular unit which can be arranged on a water storage unit.
 3. The device as claimed in claim 1, wherein at least one of the flush pipes is controlled by a solenoid, wherein the core of the solenoid is connected to a spring.
 4. The device as claimed in claim 3, wherein the solenoid is further provided with a permanent magnet.
 5. The device as claimed in claim 4, wherein the permanent magnet is arranged in the core of the solenoid.
 6. A system for reusing greywater, comprising: a collecting reservoir for collecting therein greywater supplied via a water feed; a storage tank for storing water; siphoning means for siphoning water from the collecting reservoir to the storage tank; and a device for discharging stored water to a water user therewith comprising: a housing for receiving therein greywater supplied via a greywater feed; a first flush pipe extending downward from the housing and connected directly to a sewer outlet; and a second flush pipe extending downward from the housing and connected to a water user.
 7. The greywater system as claimed in claim 6, wherein the siphoning means comprise: a siphon connection for siphoning water collected in the collecting reservoir from the collecting reservoir to the storage tank; pressure regulating means for thereby regulating the pressure in the storage tank, with which possible overpressure in the storage tank can be relieved so that siphoning of water from the collecting reservoir to the storage tank can take place; and wherein the siphon connection is arranged substantially in a middle zone B of the collecting reservoir which is arranged substantially upright.
 8. The greywater system as claimed in claim 6, wherein the collecting reservoir and the storage tank form part of an integrally manufactured water storage unit.
 9. The greywater system as claimed in claim 6, further comprising: a water user, particularly a toilet, not having its own water reservoir; and wherein the device for discharging stored water is adapted to thereby discharge stored water to the water user for immediate use thereof without interposing of a water reservoir of the water user.
 10. The greywater system as claimed in claim 6, further comprising: determining means for determining the quantity of water stored in the system; and influencing means for thereby influencing the quantity of water flowing from the storage tank to a water user.
 11. The greywater system as claimed in claim 6, wherein the collecting reservoir comprises a volume of at least 10 litres so that sufficient greywater for at least two successive flushes can be stored therein.
 12. The greywater system as claimed in claim 10, wherein the influencing means comprise a throttle or pinch valve controlled by a control system of the greywater system.
 13. The greywater system as claimed in claim 10, wherein the influencing means, controlled by a control system of the greywater system, adjust the period of time for which the flush opening is open.
 14. The greywater system as claimed in claim 6, further comprising: a conduit system between the storage tank and a water user located at some distance; and a pump for thereby pumping water out of the storage tank to the water user.
 15. The greywater system as claimed in claim 14, wherein the basic volume of water present in the storage tank is increased for each additional water user connected to the system.
 16. The greywater system as claimed in claim 15, wherein at least 10 litres of water is adhered to as basic volume for two water users.
 17. (canceled)
 18. (canceled) 